The nice ones are almost all old business cars. The business car was used by the railroads for senior executives to move around their systems, and hold meetings.. usually contain a couple of executive bedrooms, a staff bedroom (they typically carried a cook and a steward, although the roles were sometimes combined). The rear half or so of the car is an open plan lounge/meeting room.

The cars were usually built by a company like Pullman, usually from a time frame of roughly 1900 +/- 20 years.

Huge money pits, with tons of (often quite ornate) wood m, etc. then add the cost of restoration (again almost all of these cars are 100+ years old), retrofitting modern electrical systems, air conditioning. Could easily be a million dollar project.

so basically all the problems of buying a castle or old chateau, but on wheels.